To meet the demand for wireless data traffic having increased since deployment of 4G (4th-Generation) communication systems, efforts have been made to develop an improved 5G (5th-Generation) or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a ‘beyond 4G network’ or a ‘post LTE system’.
The 5G communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed in 5G communication systems.
In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud radio access networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, coordinated multi-points (CoMP), reception-end interference cancellation and the like.
In the 5G system, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as an advanced access technology have been developed.
D2D communication is being researched for enabling discovery and data communication services between user equipments (UEs). Discovery is a process for determining that a D2D-enabled UE is present adjacent to another D2D-enabled UE. Discovering a D2D-enabled UE determines whether another D2D-enabled UE is interested in using D2D discovery. A D2D-enabled UE may have interest in discovering another D2D-enabled UE when its proximity needs to be known by one or more authenticated applications by discovering a D2D-enabled UE. For example, a social networking application may be enabled to use D2D discovery. D2D discovery may enable the D2D-enabled UE of a particular user of the social networking application to discover his friends' D2D-enabled UEs or allow for discovery by the friends' D2D-enabled UEs. As another example, D2D discovery may enable discovery of, e.g., shops or restaurants of interest, which are located near the D2D-enabled UE of a particular of a search application. A D2D-enabled UE may discover other nearby D2D-enabled UEs using direct UE-to-UE signaling.
In a conventional method, when discovery is supported for a cell (or serving cell) camping on a carrier F1 to send discovery messages, a UE may obtain discovery resources for sending discovery messages on the F1 carrier from the serving cell on the F1 carrier. The serving cell may broadcast discovery resource configurations in system information block 19 (SIB 19). SIB 19 may deliver resource pools for transmission of discovery messages. A UE may use such resources to send discovery messages in an idle state. When there is no resource pool for transmission or UE is in a connected state, a D2D UE should send a request for resources for sending discovery messages on the F1 carrier to the serving cell on the F1 carrier using dedicated signaling.
In another conventional method, while camping on a serving cell on a carrier F1, a D2D UE may be permitted to send discovery messages on another carrier F2. This may be referred to as inter-carrier discovery communication. Unless discovery is supported by the serving cell on carrier F1 or carrier F1 is a frequency at which a D2D UE desires to send discovery messages, the D2D UE may send discovery messages. The serving cell on carrier F1 may provide an assistance for obtaining resources for discovery transmission on carrier F2. In other words, the serving cell may provide resources for discovery transmission on carrier F2 in SIB 19 or dedicated signaling.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.